The invention relates to an aiming device, that is, a diopter, with a tubular housing portion and with an eyepiece including a diaphragm formed by an axially slotted sleeve member providing lamellas with free end portions bent inwardly toward the diopter axis so as to define the diaphragm opening. The inwardly bent end portions of the lamellas extend normal to the diopter axis and are disposed in overlapping relationship. They are arranged with their outer edge in engagement with a conical section of the eyepiece housing into which the sleeve member may be forced by means of a hollow, knurled screw member which is screwed into the eyepiece housing, the eyepiece housing being mounted to the diopter housing. The housing portion also contains a polarization filter consisting of two polarizing discs disposed adjacent one another and being rotatable relative to one another by 90.degree. by means of knurled rings and it further contains a color filter consisting of a disc rotatable by another knurled ring and including a plurality of different color filters wherein the knurled screw member and the knurled rings all have about the same outer diameter and are arranged coaxially with respect to the tubular housing portion in such a manner that the knurled rim areas project only slightly from the tubular housing portion. Such a diopter sight with integral eyepiece, color and polarizing filters is known for example from Applicant's earlier U.S. Pat. No. 4,392,723 which issued July 12, 1983.
This sight provides for a combination diopter which permits not only for adjustment of the diaphragm by way of an annular knurled screw surrounding a tubular diaphragm housing but also for the setting of the polarization filter discs and the selection of the color filters as desired by the operator or the hunter, all by the same type of operating mechanism. This arrangement has the advantage that the hunter can change the setting of the diaphragm and of the polarizing filter as well as the color filters all in the same manner while he is aiming essentially without a change in his hand position. Also such an aiming device is very compact, short and light so that the recoil forces have little effect on the device and alignment errors remain within acceptable limits.
The prior art includes also aiming devices without a housing portion as it is known from the patent just described. Rather those prior art arrangements utilize separate parts, that is, eyepieces, polarizing filters and color filters, which are placed next to, and screwed to, one another. Such a device however is not only quite long so that component alignment errors are more seriously affecting the device's performance but the device is also much more difficult to handle and to adjust as the position of the operator's hand must be changed for the various adjustments.
The aiming device described in U.S. Pat. No. 4,392,723 has proved itself extraordinarily well, but the owners find it disadvantageous that they cannot clean it themselves. Since all the components are firmly mounted within a tubular housing, adjustment of the components is permanent and the device is very compact but servicing procedures are quite involved and cannot be performed by a normal owner since reliable performance cannot be expected after servicing of such a device by a layman. This is especially true with regard to the polarizing filter whose filter plates are mounted on support arms which can be pivoted relative to one another and together out of the center of the light passage. The arrangement requires a combination of the two filter plates with the operating arms which prevents cleaning of the polarizing filter plates. In addition, also the eyepiece and the color filter are not easily accessible for cleaning.
It is also considered to be a disadvantage that, if the polarizing filter is pivoted to its operating position in the line of sight, there are necessarily two filter plates in place which darken the view even if both are arranged in the same direction of polarization.
Finally, it is pointed out that the prior art arrangement does not lend itself well to automatic assembly, that is, to economic assembly in large numbers.
It is the object of the present invention to provide an aiming device which can be manufactured economically but which is still compact, that is, a device in which the eyepiece and the various filters are disposed closely adjacent one another and still is provided with the knurled operating rings disposed around the tubular housing but which, nevertheless, can be easily disassembled for cleaning and again assembled by the owner.